1. Field of the Invention
The present invention relates to wireless telecommunications, more particularly, identifying alternative service options.
2. Description of the Prior Art
The mechanism defined in IS-95B (the IS-95B Telecommunications Standard is hereby incorporated by reference) to allow the mobile station (MS) to specify up to seven alternate service options in the Origination and Page Response messages to the Base Station (BS). This mechanism suffers from time-consuming service negotiation request/response cycles in the event that the initial service option proposed by the MS was unacceptable to the BS.
This mechanism is potentially wasteful of bits on the Access Channel. Specifically, the current technique devotes 3 bits to NUM_ALT_SO (the number, from 0 to 7, of alternative service options the MS is proposing) in Origination and Page Response, plus an additional NUM_ALT_SOxc3x9716 bits for the list of service option numbers. Specifying even a single alternative service option therefore requires 19 bits, and specifying more than one becomes unattractive due to the overhead involved.
Despite the fact the service option is a 16-bit number, fewer than two dozen unique service options have been defined to date (per PN-4158/TSB58-A). Although that number is expected to grow in the future, it is hard to imagine enough new service options will be defined as to outgrow a bitmap mechanism that is to be proposed and is sufficiently robust.
To impose order on the existing arbitrary service option number assignments, the present invention divides them into related groups. One group comprises voice service options: #1 (TIA/EIA-96-C xe2x80x9cbasicxe2x80x9d 8k), #3 (IS-127 EVRC 8k), and #17 (IS-733 13k) which refer to different voice encoding rates. Other groups may include data services; however, several subgroupings are possible, and may be used to keep the size of each group at a manageable level. The TIA/EIA-96-C is hereby incorporated by reference.
Definitions for each related group of service options (i.e., bitmap) would be maintained in a standard such as TSB58. The TSB58 standard is hereby incorporated by reference.